1. Field of the Invention
This invention relates to a method and apparatus for feeding material to be pressed to a press or withdrawing pressed material therefrom, and more particularly to a method and apparatus for feeding a material to be pressed to a high speed press.
2. Description of the Prior Art
In a conventional method of feeding materials to be pressed, pressed material on a metal mold provided in a press is withdrawn therefrom by a carry-out arm and untreated material is then placed on the metal mold by a carry-in arm. After the material is pressed, the pressed material is withdrawn again in the same manner. The material to be pressed and the pressed material are fed onto and sent out from the metal mold in the mentioned order to carry out a pressing operation. In order to replace a pressed material on a metal mold with an untreated material, the pressed material is carried to the outside of a zone in which an upper metal mold is vertically moved, and the untreated material is then carried onto the metal mold to be inserted therein.
Therefore, it takes a great deal of time to replace pressed material with material to be pressed. In order to carry out such replacement of materials, it is necessary to reduce the speed of operation of the press or temporarily stop the operation thereof. This prevents an increase in the feed rate of materials to be pressed and the productivity of pressed materials.
In operation, when the pressed material on the metal mold is replaced with the material to be pressed, by the carry-out arm and the carry-in arm, each of which has a , means for gripping a substantially intermediate portion of the respective material, it is necessary that the movements of three parts, i.e. the gripper means on the carry-out arm, the gripper means on the carry-in arm, and the vertically displaceable upper metal mold do not obstruct one another in the space above the lower metal mold. Therefore, it is necessary to carry out the replacement of the pressed material with the material to be pressed, after the upper metal mold is lifted sufficiently, and lower the upper metal mold after the replacement of the material is completed with the gripper means on the carry-in arm moved to the outside of a zone in which the upper metal mold is moved downward.
Thus, in a conventional apparatus for feeding materials to be pressed, in which much time is required for carrying out the replacement of the material and the transfer of a gripper means to the outside of the zone of movement of the upper metal mold, the speed of operation of the press and the productivity of pressed materials cannot be increased.
Furthermore, the operation of replacing the metal mold in the press, which is done as necessary, becomes complicated since the operation is obstructed by the carry-in and carry-out means which are provided on the front surface of the bolster. Namely, the conventional apparatus for feeding materials to be pressed cannot adapt itself speedily to the re-arrangement of the production line.